One known mechanical arrangement for processing pipes by cutting using a cutting beam includes a cutting head, a pipe holder, a catching lance and a stripper. The cutting beam may be directed from the cutting head onto a pipe to be processed, along a processing axis of the cutting head, which axis forms the cutting beam axis when the cutting beam is switched on and is in the transverse direction of the pipe. The cutting beam and the pipe are movable relative to each other in the circumferential direction of the pipe, with at least one pipe portion being severed. The pipe holder, viewed in the longitudinal direction of the pipe, is disposed on one side of the processing axis of the cutting head and is provided for fixing the pipe to be processed. The stripper is disposed on that side of the processing axis of the cutting head which is opposite the pipe holder in the longitudinal direction of the pipe. The catching lance is insertable into the interior of the pipe to be processed on that side of the processing axis of the cutting head which is opposite the pipe holder in the longitudinal direction of the pipe and may in so doing be arranged with a projecting length relative to the stripper in the longitudinal direction of the pipe and towards the processing axis of the cutting head. The at least one severed pipe portion may be deposited on the catching lance on the side of the stripper which is towards the processing axis of the cutting head, and the pipe portion(s) deposited on the catching lance may be stripped off the catching lance by the stripper by virtue of the catching lance being movable relative to the stripper in the longitudinal direction of the pipe with a withdrawal movement away from the processing axis of the cutting head.
A mechanical arrangement of the kind described above is sold by the company TRUMPF©, 71254 Ditzingen, Germany, under the product name TUBEMATIC® RC. It is known in the prior art, to use such a device, with a laser cutting beam produced in a laser cutting head, for the cutting of pipe portions from long metal pipes. For that purpose, the pipe to be processed is clamped by a longitudinal end in a chuck that is rotatable about the axis of the pipe and which is for its part mounted on a feed carriage which is displaceable in the longitudinal direction of the pipe. To sever the individual pipe portions, the pipe to be processed is repositioned by displacing the feed carriage relative to the laser cutting head in the longitudinal direction of the pipe by the respective pipe portion length. During the repositioning movement of the pipe to be processed, the laser cutting head is in its inoperative state. Following a repositioning movement, the laser cutting beam is directed onto the pipe to be processed and the pipe is rotated about the pipe axis by rotating the chuck disposed on the feed carriage. By that means the laser cutting beam makes a continuous severing cut in the circumferential direction of the pipe. On the side of the laser cutting head which is opposite the chuck and the feed carriage in the longitudinal direction of the pipe, a catching lance in the form of a so-called “catcher” is arranged. The catcher is a cooling and/or flushing lance of the kind described in detail in EP 1 454 700 A1.
Before processing of a pipe by cutting is commenced, the catcher, mounted on a catcher slide, is moved relative to the laser cutting head in the longitudinal direction of the pipe into a working position. Once the catcher is in the working position, the processing axis of the laser cutting head extends through a collecting aperture made in the wall of the catcher. Between the laser cutting head and the catcher slide, a stripper is rigidly mounted on the machine bed of the prior-known arrangement, i.e. is mounted such that its position does not change. When the catcher is in the working position, the stripper is arranged close to the catcher slide and the catcher passes through it in the longitudinal direction of the pipe.
When the pipe to be processed is being positioned in the longitudinal direction of the pipe prior to the making of a severing cut, the catcher runs into the interior of the pipe at the longitudinal end of the pipe facing it. Metal spatter produced in the interior of the pipe during the cutting operation passes through the collecting aperture in the wall of the catcher into the interior of the catcher and is removed therefrom. When the severing cut has been completed, the severed pipe portion is deposited under the action of gravity on the catcher. With the laser cutting beam switched off, the pipe to be processed is then repositioned by displacing the feed carriage in the longitudinal direction of the pipe. The end of the pipe that is the leading end in the repositioning operation shifts the pipe portion already deposited on the catcher in the direction towards the catcher slide. If a second severing cut is now made, the pipe portion severed in the process is also deposited on the catcher. These procedures may be repeated until the entire length of the catcher is occupied by pipe portions threaded onto it. The catcher slide then travels, together with the catcher mounted on it, in the longitudinal direction of the pipe away from the laser cutting head. The pipe portions threaded on the catcher are consequently stripped off the catcher by the stripper mounted in a fixed position on the machine bed of the prior-known arrangement and fall onto an unloading ramp where they are finally removed from the vicinity of the mechanical arrangement.